DESCRIPTION (Investigator's Abstract) "Glaucoma is one of the leading causes of blindness in the United States and other industrialized countries. It is now recognized that glaucoma is the leading cause of blindness among African Americans. It is also one of the most common causes of blindness in individuals above age 60, one of the fastest growing groups in the United States. Elevated intraocular pressure (IOP) has been noted to be the key risk factor for the development of open angle glaucoma. However, there is no clear consensus on whether early treatment of elevated IOP prevents or delays the onset of open-angle glaucoma. This is an application to become a participating Clinical Center in the Ocular Hypertension Treatment Study (OHTS), a long-term, randomized, multicenter clinical trial to determine whether medical reduction of IOP prevents or delays the onset of glaucomatous optic nerve and/or visual field damage in ocular hypertensive subjects. The complete details of the OHTS rationale, design, and methods are contained in the OHTS Manual of Procedures. This proposal provides complete documentation of the ability of the University of Michigan to screen large numbers of ocular hypertensive patients and to enroll at least 50 eligible patients over a 24 month period. Documentation is provided of the capabilities of the proposed investigators and their staff for the performance of the study in accord with the details of the OHTS Manual of Procedures, the nature and extent of their commitment to the University of Michigan and the participation of community ophthalmologists."